It is known to construct lightweight structural components of high mechanical strength in the form of a sandwich type structure having upper and lower cover sheets made of fiber compound materials with a honeycomb type core sandwiched between the cover sheets, whereby the core is usually made of metal, mostly aluminum which is glued to the cover sheets. The use of a honeycomb type core made of aluminum or similar material suitable for forming a supporting core has the advantage that it may be relatively simply deformed prior to the curing or hardening of the cover layers made of fiber compound materials provided that the deforming remains within certain limits. Accordingly, it is possible to construct the sandwich type structural components with a curved surface in an economical manner.
However, it has been found that problems arise where the different thermal expansion coefficients of the cover surface material and of the core material can result in a deformation of the curved surface, especially where the structural component is exposed to temperature variations under which it becomes unable to retain its dimensional stability, especially with regard to the shape of its curved surface. Such deformations have been found to occur, especially where the cover layers have been made of high strength carbon fibers having an extremly low heat expansion coefficient while the core is made of a material having a larger heat expansion coefficient. Thus, in connection with radio telescope mirrors having, for example, a diameter of more than ten meters, and being assembled of a plurality of paraboloidal mirror segments it has been difficult heretofore to assure a constant, exact focusing due to different heat expansions of the core relative to the curved surface when such mirrors are exposed to large temperature differences during the course of a day. Similar problems have been encountered where the molding tools for the formation of such mirror segments are also to be produced as sandwich components with fiber compound material cover layers because such molding tools may also be exposed to different temperatures during the manufacturing process of the structural components such as mirror segments or the like.